Adding deprecation notice to repo (helm#24417)

Signed-off-by: Matt Farina <[email protected]>

Author: mattfarina

README.md

@@ -1,8 +1,11 @@
+|![](https://upload.wikimedia.org/wikipedia/commons/thumb/1/17/Warning.svg/156px-Warning.svg.png) | This project is no longer supported.
+|---|---|
+
 # Helm Charts
 
-The canonical source for Helm charts is the [Helm Hub](https://hub.helm.sh/), an aggregator for distributed chart repos.
+The canonical source for Helm charts is the [Artifact Hub](https://artifacthub.io), an aggregator for distributed chart repos.
 
-This GitHub project is the source for Helm `stable` and `incubator` [Helm chart repositories](https://v3.helm.sh/docs/topics/chart_repository/), currently listed on the Hub.
+This GitHub project is the source for Helm `stable` and `incubator` [Helm chart repositories](https://v3.helm.sh/docs/topics/chart_repository/). This is now an archive no longer under active development.
 
 For more information about installing and using Helm, see the
 [Helm Docs](https://helm.sh/docs/). For a quick introduction to Charts, see the [Chart Guide](https://helm.sh/docs/topics/charts/).